Carbon-supported platinum-based alloy catalyst as well as preparation method and application thereof

Abstract

The invention provides a carbon-supported platinum-based alloy catalyst and a preparation method and application thereof, and the preparation method of the carbon-supported platinum-based alloy catalyst comprises the following steps: providing an impregnation liquid containing a platinum source and a non-noble metal source; dispersing and impregnating a carbon-based carrier in the impregnation liquid, and removing moisture to obtain a precursor mixture; and calcining and annealing the precursor mixture in a mixed atmosphere containing hydrogen, carbon monoxide and inert gas to obtain the carbon-supported platinum-based alloy catalyst.

Description

Technical Field

[0001] The present disclosure relates to the technical field of nanomaterials, and in particular to a carbon-supported platinum-based alloy catalyst and a preparation method and application thereof. Background Art

[0002] The precious metal platinum has become one of the main industrial catalyst materials due to its excellent catalytic activity in key industrial catalytic reactions such as propane dehydrogenation, oxygen reduction, hydrogen evolution and water vapor shift. However, traditional bulk platinum catalysts are difficult to achieve efficient and economical industrial applications due to their low active specific surface area and atomic utilization. For this reason, supported nanocatalysts are considered ideal alternatives due to their high active specific surface area and atomic utilization.

[0003] At present, the industry mainly uses the impregnation-reduction method to prepare supported platinum-based nanocatalysts, but this method easily leads to large platinum particle size and uneven distribution, which in turn affects the catalytic performance. Although the solvent thermal reduction method can synthesize uniform platinum-based nanocrystals, its large-scale application is limited due to the high cost of solvents and difficulty in product separation. Although the thermal stability of platinum-based nanoparticles has been effectively improved through methods such as carrier functionalization modification and doping, it still faces the problems of complex synthesis steps and high production costs. In addition, due to the limited stabilizing effect of modification and doping methods, the active metal content in the resulting alloy catalyst is often low (less than 50 wt%), which is difficult to meet the needs of efficient catalysis.

[0004] Therefore, developing a new method that can efficiently synthesize small-sized, highly active platinum-based nanocatalysts while also being economically feasible and industrially applicable has become a technical challenge that needs to be solved urgently and is of great significance to promoting the development of the field of industrial catalysis. Summary of the invention

[0005] In view of this, the main purpose of the present disclosure is to provide a carbon-supported platinum-based alloy catalyst and a preparation method and application thereof, in order to at least partially solve at least one of the above-mentioned technical problems.

[0006] To achieve the above purpose, the technical solution of the present invention is as follows:

[0007] In one aspect of the present disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst is provided, comprising:

[0008] Providing an impregnation solution containing a platinum source and a non-precious metal source;

[0009] dispersing and impregnating the carbon-based support in an impregnation solution, removing water, and obtaining a precursor mixture;

[0010] The precursor mixture is calcined and annealed in a mixed atmosphere of hydrogen, carbon monoxide and inert gas to obtain a carbon-supported platinum-based alloy catalyst.

[0011] In another aspect of the present disclosure, a carbon-supported platinum-based alloy catalyst prepared by the above-mentioned preparation method is provided, wherein the carbon-supported platinum-based alloy catalyst comprises a carbon-based carrier and platinum-based alloy nanoparticles loaded on the surface of the carbon-based carrier; wherein the platinum-based alloy nanoparticles are an alloy of platinum and non-precious metals.

[0012] In yet another aspect of the present disclosure, there is provided a use of the carbon-supported platinum-based alloy catalyst in an oxygen reduction reaction.

[0013] According to an embodiment of the present disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst is provided, wherein water is used as a solvent, a platinum source is mixed with a non-precious metal source to obtain an impregnation solution, and a carbon-based carrier is directly impregnated in the impregnation solution to remove water to obtain a precursor mixture, thereby reducing costs and reducing solvent pollution. Then, the precursor mixture is calcined and annealed in a mixed atmosphere of hydrogen, carbon monoxide, and an inert gas, thereby preparing a high-performance carbon-supported platinum-based alloy catalyst. During the preparation process, the hydrogen in the mixed atmosphere can quickly reduce the platinum in the precursor mixture, and the carbon monoxide can effectively inhibit the rapid growth of platinum clusters or platinum nanoparticles, causing their size to increase slowly, thereby ensuring the size uniformity and stability of the platinum nanoparticles. A carbon-supported platinum-based alloy catalyst with a smaller size and a higher loading is prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure taken by an atomic-level resolution scanning transmission electron microscope;

[0015] Figure 2 This is a high-angle annular dark-field image of a carbon-supported platinum-cobalt alloy catalyst taken by a scanning transmission electron microscope in Example 1 of the present disclosure;

[0016] Figure 3 is a particle size distribution diagram of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure;

[0017] Figure 4 is an X-ray diffraction spectrum of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure;

[0018] Figure 5 is a polarization curve diagram of the oxygen reduction reaction catalyzed by a commercially available platinum-carbon catalyst and the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure under the same loading conditions;

[0019] Figure 6 is an X-ray diffraction spectrum of the carbon-supported platinum-nickel alloy catalyst in Example 2 of the present disclosure;

[0020] Figure 7This is a high-angle annular dark field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 of the present disclosure taken by an atomic-level resolution scanning transmission electron microscope;

[0021] Figure 8 This is a bright field image of a transmission electron microscope of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 2 of the present disclosure;

[0022] Fig. 9 This is a bright field image of a transmission electron microscope of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 3 of the present disclosure;

[0023] Fig.10 is the X-ray diffraction spectrum of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of the present disclosure;

[0024] Fig.11 It is the X-ray diffraction spectrum of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of the present disclosure. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments.

[0026] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in this disclosure.

[0027] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0028] Platinum-based catalysts are catalysts with platinum as the main active component, and are divided into pure platinum catalysts and platinum alloy catalysts. Platinum alloy catalysts are further divided into disordered platinum alloy catalysts and platinum intermetallic compound catalysts based on whether the atomic arrangement is regular. Due to its excellent catalytic activity, platinum has shown outstanding performance in many key industrial reactions, making platinum-based catalysts an important catalyst with great commercial value. However, precious metals such as platinum are scarce in the earth's crust. Therefore, compared with pure platinum, platinum alloys have richer and more adjustable local coordination environments and electronic structures. Supported nano-platinum-based alloy catalysts are regarded as ideal substitutes for traditional bulk catalysts due to their high active specific surface area and atomic utilization.

[0029] In the process of realizing the concept of the present disclosure, it was found that although the impregnation-reduction method and solvent thermal reduction method commonly used in industry can be used to prepare supported platinum-based nanocatalysts, there are still many problems, such as large and uneven distribution of platinum particles, high solvent cost and difficulty in separation, cumbersome synthesis process, low active metal content of alloy catalysts, etc., which limit their large-scale application.

[0030] Therefore, the present disclosure proposes a method based on aqueous solution impregnation to prepare a carbon-supported platinum-based alloy catalyst, using water as a solvent, mixing a platinum source and a non-precious metal source to obtain an impregnation solution, and dispersing and impregnating the carbon-based carrier in the impregnation solution, thereby reducing costs and reducing solvent pollution. By regulating the reducing atmosphere, hydrogen can quickly reduce the platinum source to initially form platinum clusters or platinum nanoparticles. Since platinum metal has a high adsorption capacity for carbon monoxide, carbon monoxide is adsorbed on the surface of the initially formed platinum clusters or platinum nanoparticles, effectively inhibiting their growth, so that the reduced platinum nanoparticles are alloyed with non-precious metals to form small-sized platinum alloy nanoparticles. Furthermore, by optimizing the calcination and annealing process, the size of the nanoparticles can be further controlled, and at the same time, the conversion to ordered alloy nanoparticles (i.e., intermetallic compounds) can be achieved, thereby improving the catalytic activity of the catalyst. The preparation method disclosed in the present invention does not require the use of organic solvents, metal organic salts or sacrificial agents, template agents and other additives, simplifies the preparation process and has mild reaction conditions, reduces production costs, and can achieve large-scale preparation of carbon-supported platinum-based alloy catalysts while ensuring the small size, high loading and high activity of the catalyst. It has significant economic feasibility and industrial applicability, and provides a new technical path for the preparation of platinum-based catalysts.

[0031] According to an embodiment of one aspect of the present disclosure, a method for preparing a carbon-supported platinum-based alloy catalyst is provided, comprising:

[0032] Providing an impregnation solution containing a platinum source and a non-precious metal source; dispersing and impregnating a carbon-based carrier in the impregnation solution, removing water, and obtaining a precursor mixture; calcining and annealing the precursor mixture in a mixed atmosphere including hydrogen, carbon monoxide and an inert gas to obtain a carbon-supported platinum-based alloy catalyst.

[0033] According to an embodiment of the present disclosure, the present disclosure provides a method for preparing a carbon-supported platinum-based alloy catalyst based on aqueous solution impregnation. By using water as a solvent, a platinum source is mixed with a non-precious metal source and then directly impregnated on a carbon carrier, thereby achieving cost reduction and reducing solvent pollution. In the preparation process, a mixed gas of hydrogen, carbon monoxide and an inert gas is used as an atmosphere for calcination and annealing. The hydrogen first quickly reduces the platinum precursor to form primary platinum clusters or extremely small platinum nanoparticles. Subsequently, carbon monoxide is adsorbed on the surface of the platinum clusters and extremely small nanoparticles, effectively inhibiting the rapid growth of the platinum clusters and extremely small nanoparticles, causing their size to increase slowly. As the temperature further increases, the non-precious metal salt is reduced, and the reduced non-precious metal is alloyed with smaller-sized platinum nanoparticles, and finally small-sized platinum alloy nanoparticles are formed on the carbon carrier, thereby preparing a small-sized, high-load carbon-supported platinum-based alloy catalyst.

[0034] According to an embodiment of the present disclosure, the content of hydrogen in the mixed atmosphere is 3% to 10%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc., preferably 5% to 8%. Hydrogen is mainly used to reduce the precursor to form platinum alloy nanoparticles. When the hydrogen content is too low (such as less than 3%), the reduction rate is slow, which may lead to incomplete reduction of the platinum precursor and affect the activity of the catalyst; when the hydrogen content is too high (greater than 10%), the reduction rate is too fast, which may cause the platinum nanoparticles to grow rapidly and become too large in size, reducing the specific surface area and activity of the catalyst.

[0035] The carbon monoxide content is 1% to 15%, for example, 1%, 5%, 7%, 10%, 13%, 15%, 19%, etc., preferably 5% to 10%. Carbon monoxide is adsorbed on the surface of platinum alloy nanoparticles, inhibiting their rapid growth and causing the particle size to increase slowly. When the carbon monoxide content is too low (e.g., less than 1%), the inhibitory effect is insufficient, and the platinum alloy nanoparticles may grow rapidly, resulting in an oversized size; when the carbon monoxide content is too high (e.g., greater than 15%), the growth of platinum nanoparticles may be excessively inhibited, resulting in a particle size that is too small, affecting the stability and selectivity of the catalyst.

[0036] The content of the inert gas is 75% to 96%, for example, 75%, 80%, 83%, 85%, 87%, 90%, 96%, etc. The inert gas includes any one of argon, helium, and nitrogen. The inert gas acts as a balancing gas to adjust the total pressure of the mixed atmosphere and the partial pressure of each component, while providing a stable calcination and annealing environment.

[0037] According to the embodiments of the present disclosure, the ratio of hydrogen, carbon monoxide and inert gas in the mixed atmosphere can effectively control the size of platinum-based alloy nanoparticles. Hydrogen reduces the precursor, carbon monoxide inhibits particle growth, and inert gas provides a stable environment. The three work synergistically to ensure the size, activity and stability of platinum alloy nanoparticles, thereby improving the overall performance of carbon-supported platinum-based alloy catalysts.

[0038] According to an embodiment of the present disclosure, the flow rate of the mixed atmosphere is 10-150 sccm, for example, 10 sccm, 30 sccm, 50 sccm, 80 sccm, 100 sccm, 130 sccm, 150 sccm, etc. The flow rate within this range can ensure sufficient contact between the components while avoiding too fast or too slow reaction rate, thereby achieving uniformity and controllability of the reaction.

[0039] According to an embodiment of the present disclosure, the platinum source includes any one of chloroplatinic acid, platinum acetylacetonate, platinum tetraammine nitrate, potassium chloroplatinate, sodium chloroplatinate, and ammonium chloroplatinate. The non-precious metal source is a soluble non-precious metal salt, and the soluble non-precious metal salt is selected from any one of nitrates or chlorides of vanadium, chromium, manganese, iron, cobalt, nickel, copper, and zinc. Specifically, it can be any one of vanadium trichloride, chromium chloride hexahydrate, manganese nitrate tetrahydrate, manganese chloride, iron nitrate nonahydrate, iron trichloride, cobalt nitrate hexahydrate, cobalt chloride hexahydrate, nickel nitrate hexahydrate, nickel chloride hexahydrate, copper nitrate trihydrate, copper chloride dihydrate, zinc nitrate hexahydrate, and zinc chloride. The carbon-based carrier can be commercial carbon black, specifically any one of Ketjen Black EC300-J, Ketjen Black EC600-JD, BP2000, and XC-72R. The present disclosure can prepare different types of carbon-supported platinum-based alloy catalysts by changing the types of platinum sources and non-precious metal sources to meet diverse industrial needs.

[0040] According to an embodiment of the present disclosure, the molar ratio of the non-precious metal source and the platinum source is (0.3~1.5):1, for example, it can be 0.3:1, 0..5:1, 0.8:1, 1:1, 1.5:1, etc. By controlling the molar ratio of the non-precious metal salt to the platinum precursor, the degree of alloying can be effectively controlled. When the molar ratio of the non-precious metal source and the platinum source exceeds the range of 1.5:1, the loading of the non-precious metal in the formed alloy may be too high, which reduces the stability of the catalyst in the oxygen reduction application process and is not conducive to the formation of an ordered alloy; if the molar ratio of the non-precious metal source and the platinum source is too low (lower than 0.3:1), the platinum-based alloy cannot be effectively formed, and it is also not conducive to the formation of an ordered alloy.

[0041] The mass ratio of the carbon-based carrier, the platinum source and the non-precious metal source is 2: (6-10): (1.2-4.5), for example, 2: 6: 1.2, 2: 8: 2, 2: 10: 3, 2: 10: 3.5, 2: 10: 4.5, etc. By adjusting the amount of the carbon-based carrier added, the loading amount of the platinum-based alloy particles on the catalyst can be regulated to ensure the uniformity and catalytic activity of the carbon-supported platinum-based alloy catalyst.

[0042] According to an embodiment of the present disclosure, dispersing and impregnating the carbon-based carrier in an impregnation solution includes: mixing a platinum source and a non-precious metal source in an aqueous solution to obtain an impregnation solution with a concentration of 4 to 18 mmol / L; impregnating the carbon-based carrier in the impregnation solution for 2 to 20 hours, and removing water to obtain a precursor mixture. The concentration of the impregnation solution can be, for example, 4 mmol / L, 6 mmol / L, 8 mmol / L, 9 mmol / L, 12 mmol / L, etc., and the impregnation time can be, for example, 2 h, 4 h, 6 h, 8 h, 10 h, 15 h, 20 h, etc., preferably 5 to 15 h, and more preferably 8 to 10 h.

[0043] According to the embodiments of the present disclosure, by wet impregnation, the concentration of the impregnation solution and the time of impregnation are controlled, and the dispersion degree of the precursor mixture on the carbon-based support is effectively adjusted, which is conducive to controlling the particle size of the small-sized and high-loaded carbon-supported platinum-based alloy catalyst. For example, at an impregnation solution concentration of 6 to 12 mmol / L and an impregnation time of 8 to 12 h, platinum-based alloy nanoparticles with a particle size of 3 nm to 5 nm can be obtained, thereby obtaining a carbon-supported platinum-based alloy catalyst with a smaller particle size. In addition, compared with the preparation method of preparing the catalyst in an organic solvent, the preparation method based on aqueous solution impregnation can achieve large-scale preparation of carbon-supported platinum-based alloy catalysts while reducing preparation costs.

[0044] According to an embodiment of the present disclosure, calcination and annealing include: first heating the precursor mixture to a calcination temperature of 600°C~1100°C at a rate of 0.5~5°C / min, keeping the temperature for reaction for 0.5~2 h, then cooling to an annealing temperature of 450°C~700°C at a rate of 0.1~3°C / min, and cooling to room temperature to obtain a carbon-supported platinum-based alloy catalyst.

[0045] According to the embodiments of the present disclosure, the heating rate can be, for example, 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, 4°C / min, 5°C / min, etc., and the appropriate calcination heating rate helps to control the size of the platinum-based alloy nanoparticles. When the heating rate is too fast during calcination, it is easy to cause the growth rate of the platinum-based alloy nanoparticles to be too fast, thereby affecting the size of the platinum-based alloy nanoparticles and the activity of the catalyst in the catalytic process; when the heating rate is slow during calcination, the heating time will be extended, wasting energy and time. The calcination temperature can be, for example, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, etc., preferably 800~1100°C, and more preferably 900~1100°C. A higher calcination temperature is conducive to the formation of highly alloyed platinum-based alloy nanoparticles, but an excessively high calcination temperature (above 1100 °C) can easily lead to sintering of nanoparticles in the catalyst and carbon deposition and coking, resulting in a decrease in the exposed active area of ​​the nanoparticles and a reduction in catalytic activity. An excessively low calcination temperature (below 600 °C) can easily lead to incomplete reduction and alloying of the precursor, resulting in a decrease in the non-precious metal loading in the alloy nanoparticles, which is not conducive to the formation of highly alloyed alloys and intermetallic compounds. The heat preservation reaction time can be, for example, 0.5 h, 1 h, 0.5 h, 2 h, etc., preferably 1 to 2 h.

[0046] According to the embodiments of the present disclosure, the cooling rate can be, for example, 0.1°C / min, 0.5°C / min, 1°C / min, 2°C / min, 3°C / min, etc. The annealing cooling rate will affect the structure of the platinum-based alloy nanoparticles. When the annealing cooling rate is too fast, it is easy to cause insufficient time for the atomic arrangement in the platinum-based alloy nanoparticles to be completed, resulting in a decrease in the proportion of ordered alloys, thereby affecting the activity in the catalytic process; when the annealing cooling rate is slow, the insulation time will be extended, wasting energy and time. The annealing temperature can be, for example, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, etc., preferably 480-650°C, and more preferably 500-600°C. A lower annealing temperature is conducive to the formation of highly ordered platinum-based alloy nanoparticles; however, too low an annealing temperature (below 400 °C) can easily lead to diffusion difficulties between atoms in the alloy nanoparticles, making it impossible to control the formation of small-sized ordered alloy nanoparticles; when the annealing temperature is higher than 700 °C, it is easy to convert the already formed ordered alloy nanoparticles into disordered alloy nanoparticles, resulting in a decrease in the ordered alloy loading in the alloy nanoparticles.

[0047] According to an embodiment of another aspect of the present disclosure, a carbon-supported platinum-based alloy catalyst prepared by the above-mentioned preparation method is provided, wherein the catalyst comprises a carbon-based carrier and platinum-based alloy nanoparticles supported on the surface of the carbon-based carrier; wherein the platinum-based alloy nanoparticles are an alloy of platinum and non-precious metals.

[0048] According to the embodiments of the present disclosure, the carbon-supported platinum-based alloy catalyst prepared by the preparation method of the present disclosure has a higher metal loading and a smaller platinum alloy nanoparticle size. At the same time, the platinum alloy nanoparticles contained in the catalyst can form an ordered alloy with better catalytic performance, that is, an intermetallic compound.

[0049] According to an embodiment of the present disclosure, the size of the platinum-based alloy nanoparticles is 3 to 10 nm, for example, 3 nm, 5 nm, 7 nm, 9 nm, 10 nm, etc., preferably 3 to 5 nm. The platinum-based alloy content in the catalyst is 40% to 70%, for example, 40%, 50%, 55%, 60%, 65%, 70%, etc., preferably 50% to 70%. Within the range of this size and content, the utilization rate of platinum atoms is high, which reduces the consumption of precious metals and ensures that the catalyst has a large electrochemical active surface area and intrinsic activity per unit area. This coordinated optimization of size and content enables the prepared platinum-based alloy catalyst to maintain excellent catalytic performance while also showing good economy and industrial application prospects.

[0050] According to the embodiments of the present disclosure, the proportion of ordered alloy in the alloy of platinum and non-precious metals is 30% to 50%, for example, 30%, 35%, 40%, 45%, 50%, etc. The carbon-supported platinum-based alloy catalyst prepared by the present disclosure has a high proportion of ordered alloy, and the ordered alloy structure has a regular atomic arrangement and a fixed element composition, which can form better active sites on the catalyst surface, thereby significantly enhancing the catalyst's ability to adsorb and activate reactants and improve the catalyst's catalytic reaction efficiency.

[0051] According to an embodiment of still another aspect of the present disclosure, there is provided an application of the above-mentioned carbon-supported platinum-based alloy catalyst in an oxygen reduction reaction.

[0052] According to the embodiments of the present disclosure, the carbon-supported platinum-based alloy catalyst of the present disclosure has a higher metal loading and a smaller alloy particle size. In specific applications, the carbon-supported platinum-based alloy catalyst can be widely used in oxygen reduction reactions (ORR), specifically in the cathode reactions of fuel cells. When oxygen passes through the cathode of the fuel cell, it contacts the carbon-supported platinum-based alloy catalyst on the cathode and undergoes a reduction reaction. Platinum-based alloy nanoparticles, as active sites, can quickly adsorb and activate oxygen molecules, promote their combination with electrons and protons, and thus promote the oxygen reduction reaction.

[0053] In order to make the purpose, technical scheme and advantages of the present disclosure clearer, the present disclosure is further described in detail below in conjunction with specific examples and drawings. Specific techniques or conditions not specified in the examples are all conventional methods, which can be carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. It should be noted that the methods provided in the present disclosure are all conventional methods unless otherwise specified, and the reactants and reagents can be obtained from public commercial channels unless otherwise specified.

[0054] Embodiment 1:

[0055] This embodiment 1 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, and the specific steps are as follows:

[0056] 90 mg of cobalt chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate were added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution.

[0057] 50 mg of Ketjenblack-600JD commercial carbon black was dispersed and impregnated in the impregnation solution, mixed evenly by ultrasonication, and allowed to stand for 10 h.

[0058] The eggplant-shaped bottle was connected to a rotary evaporator via a conversion joint, and most of the water was removed by the rotary evaporator to obtain a black muddy solid. The black muddy solid was rapidly cooled to freeze it. The frozen black muddy solid was freeze-dried overnight to obtain a black powder.

[0059] The black powder was transferred to a ceramic boat, and the ceramic boat was placed in the middle of a hard quartz tube. The quartz tube was then transferred to a tube furnace, and a mixed gas containing 5% hydrogen, 5% carbon monoxide, and 90% argon was introduced into the quartz tube. The ventilation was continued for 30 minutes to remove the residual air in the tube.

[0060] Under the mixed atmosphere, the tubular furnace was heated to 950 ℃ at a heating rate of 1 ℃ / min, kept for 2 h, then decreased to 600 ℃ at a rate of 0.5 ℃ / min, and then naturally cooled to room temperature to obtain a carbon-supported platinum-cobalt (PtCo) alloy catalyst, in which the loading of the platinum-cobalt alloy was about 65%.

[0061] Figure 1 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure taken with an atomic-level resolution scanning transmission electron microscope.

[0062] like Figure 1 As shown, it can be observed that the carbon-supported platinum-cobalt alloy catalyst prepared in Example 1 contains an ordered platinum-cobalt alloy.

[0063] Figure 2 This is a high-angle annular dark-field image of the carbon-supported platinum-cobalt alloy catalyst taken by a scanning transmission electron microscope in Example 1 of the present disclosure. Figure 3 Graph showing particle size distribution of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure.

[0064] like Figure 2 and Figure 3 As shown, it can be observed that the average diameter of the platinum-cobalt alloy nanoparticles in the carbon-supported platinum-cobalt alloy catalyst prepared in Example 1 is about 4 nm, wherein Figure 2 The numbers in the figure are the number of platinum-cobalt alloy nanoparticles.

[0065] Figure 4 This is the X-ray diffraction spectrum of the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure.

[0066] like Figure 4 As shown, there is an ordered platinum-cobalt alloy in the carbon-supported platinum-cobalt alloy catalyst prepared in Example 1. According to the Scherrer equation, it can be calculated that the crystal size along the (111) crystal plane is about 4 nm.

[0067] The commercially available platinum-carbon catalyst (platinum loading of 40%) and the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 were tested for catalytic oxygen reduction reaction under the same loading conditions. The specific test process is: in the electrolytic cell, 0.1 M perchloric acid is used as the electrolyte, oxygen is continuously introduced into the electrolyte to maintain oxygen saturation in the electrolyte, and the commercially available platinum-carbon catalyst and the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 are respectively dripped onto the glassy carbon electrode. The relationship between the current density and the electrode potential of the catalytic oxygen reduction of the commercially available platinum-carbon catalyst and the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 was tested using linear sweep voltammetry.

[0068] Figure 5 It is a polarization curve diagram of the oxygen reduction reaction catalyzed by the commercially available platinum-carbon catalyst and the carbon-supported platinum-cobalt alloy catalyst in Example 1 of the present disclosure under the same loading conditions.

[0069] like Figure 5 As shown, the performance of the carbon-supported platinum-cobalt alloy catalyst in catalyzing oxygen reduction reaction in Example 1 is significantly higher than that of the commercially available platinum-carbon catalyst.

[0070] Embodiment 2:

[0071] This embodiment 2 provides a method for preparing a carbon-supported platinum-nickel (PtNi) alloy catalyst, and the specific steps are as follows:

[0072] Take 95 mg of nickel chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate and add them to a 150 mL eggplant-shaped bottle, dissolve them with high-purity water, and mix them by ultrasonic to obtain 50 mL of impregnation solution;

[0073] 50 mg Ketjenblack-600JD commercial carbon black was dispersed and impregnated in the impregnation solution, mixed evenly by ultrasonication, and allowed to stand for 10 h;

[0074] The eggplant-shaped bottle is connected to a rotary evaporator via a conversion joint, and most of the water is removed by the rotary evaporator to obtain a black muddy solid. The black muddy solid is rapidly cooled to freeze it. The frozen black muddy solid is freeze-dried overnight to obtain a black powder;

[0075] The black powder was transferred to a ceramic boat, and the ceramic boat was placed in the middle of a hard quartz tube. The quartz tube was then transferred to a tube furnace, and a mixed gas containing 5% hydrogen, 10% carbon monoxide, and 85% argon was introduced into the quartz tube for 30 minutes to remove the residual air in the tube.

[0076] Under the mixed atmosphere, the tubular furnace was heated to 1100 ℃ at a heating rate of 1 ℃ / min, kept at that temperature for 2 h, then cooled to 600 ℃ at a rate of 3 ℃ / min, and then naturally cooled to room temperature to obtain a carbon-supported platinum-nickel (PtNi) alloy catalyst.

[0077] Figure 6 This is the X-ray diffraction spectrum of the carbon-supported platinum-nickel alloy catalyst in Example 2 of the present disclosure.

[0078] like Figure 6 As shown, there is an ordered platinum-nickel alloy in the carbon-supported platinum-nickel alloy catalyst prepared in Example 2. According to the Scherrer equation, the crystal size of the (111) crystal plane can be calculated to be about 5 nm.

[0079] Embodiment 3:

[0080] This embodiment 3 provides a carbon-supported platinum cobalt (Pt 3 Co) A method for preparing an alloy catalyst, the specific steps are as follows:

[0081] Take 32 mg of cobalt chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate and add them to a 150 mL eggplant-shaped bottle, dissolve them with high-purity water, and mix them by ultrasonic to obtain 50 mL of impregnation solution;

[0082] 50 mg Ketjenblack-600JD commercial carbon black was dispersed and impregnated in the impregnation solution, mixed evenly by ultrasonication, and allowed to stand for 10 h;

[0083] The eggplant-shaped bottle is connected to a rotary evaporator via a conversion joint, and most of the water is removed by the rotary evaporator to obtain a black muddy solid. The black muddy solid is rapidly cooled to freeze it. The frozen black muddy solid is freeze-dried overnight to obtain a black powder;

[0084] The black powder was transferred to a ceramic boat, and the ceramic boat was placed in the middle of a hard quartz tube. The quartz tube was then transferred to a tube furnace, and a mixed gas containing 5% hydrogen, 5% carbon monoxide, and 90% argon was introduced into the quartz tube for 30 minutes to remove the residual air in the tube.

[0085] In the mixed atmosphere, the tube furnace was heated to 1100 °C at a rate of 1 °C / min, kept at this temperature for 2 h, then cooled to 600 °C at a rate of 0.5 °C / min, and then naturally cooled to room temperature to obtain carbon-supported platinum-cobalt (Pt 3 Co) alloy catalyst.

[0086] Embodiment 4:

[0087] This Example 4 provides a method for preparing a carbon-supported platinum-copper (PtCu) alloy catalyst, which differs from Example 3 in that 75 mg of cupric chloride dihydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of an impregnation solution. The other preparation processes are the same as those in Example 3, and a carbon-supported platinum-copper (PtCu) alloy catalyst is prepared.

[0088] Example 5

[0089] This Example 5 provides a method for preparing a carbon-supported platinum-copper (PtCu) alloy catalyst, which differs from Example 3 in that 69 mg of copper chloride dihydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of an impregnation solution. The other preparation processes are the same as those in Example 3, and a carbon-supported platinum-copper (PtCu) alloy catalyst is prepared.

[0090] Example 6

[0091] This embodiment 6 provides a carbon-supported platinum zinc (Pt 3 The preparation method of the carbon-supported platinum zinc (Pt Zn) alloy catalyst is different from that of Example 3 in that 92 mg of zinc nitrate hexahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. The other preparation processes are the same as those of Example 3 to prepare carbon-supported platinum zinc (Pt 3 Zn) alloy catalyst.

[0092] Example 7

[0093] This Example 7 provides a method for preparing a carbon-supported platinum-iron (PtFe) alloy catalyst, which differs from Example 3 in that 105 mg of ferric nitrate nonahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of an impregnation solution. The other preparation processes are the same as those in Example 3, and a carbon-supported platinum-iron (PtFe) alloy catalyst is prepared.

[0094] Example 8

[0095] This embodiment 8 provides a carbon-supported platinum iron (Pt 3 The preparation method of the carbon-supported platinum iron (Pt Fe) alloy catalyst is different from that of Example 3 in that 40 mg of ferric nitrate nonahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. The other preparation processes are the same as those of Example 3 to prepare carbon-supported platinum iron (Pt 3 Fe) alloy catalyst.

[0096] Example 9

[0097] This Example 9 provides a method for preparing a carbon-supported platinum-manganese (PtMn) alloy catalyst, which differs from Example 3 in that 63 mg of manganese chloride and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of an impregnation solution. The other preparation processes are the same as those in Example 3, and a carbon-supported platinum-manganese (PtMn) alloy catalyst is prepared.

[0098] Example 10

[0099] This embodiment 10 provides a carbon-supported platinum chromium (Pt 3 The preparation method of the carbon-supported platinum chromium (Pt Cr) alloy catalyst is different from that of Example 3 in that 30 mg of chromium chloride hexahydrate and 200 mg of chloroplatinic acid hexahydrate are added to a 150 mL eggplant-shaped bottle, dissolved with high-purity water, and ultrasonically mixed to obtain 50 mL of impregnation solution. The other preparation processes are the same as those of Example 3 to prepare carbon-supported platinum chromium (Pt 3 Cr) alloy catalyst.

[0100] Embodiment 11

[0101] This embodiment 11 provides a carbon-supported platinum vanadium (Pt 3 V) alloy catalyst preparation method, the difference from Example 3 is: take 20 mg of vanadium chloride and 200 mg of chloroplatinic acid hexahydrate into a 150 mL eggplant-shaped bottle, dissolve with high-purity water, and obtain 50 mL of impregnation solution after ultrasonic mixing. The other preparation processes are the same as those in Example 3 to prepare carbon-supported platinum vanadium (Pt3 V) Alloy catalyst.

[0102] Comparative Example 1

[0103] This comparative example 1 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, which differs from Example 1 in that a mixed gas having a hydrogen content of 5% and an argon content of 95% is introduced into a quartz tube to prepare a carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0104] Figure 7 This is a high-angle annular dark field image of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 of the present disclosure taken with an atomic-level resolution scanning transmission electron microscope.

[0105] like Figure 7 As shown, it can be observed that the particle size of the nanoparticles in the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 1 is relatively large, about 50 nm.

[0106] Comparative Example 2

[0107] This comparative example 2 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, which differs from Example 1 in that a mixed gas having a carbon monoxide content of 5% and an argon content of 95% is introduced into a quartz tube to prepare a carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0108] Figure 8 This is a bright field image of a transmission electron microscope of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 2 of the present disclosure.

[0109] like Figure 8 As shown, it can be observed that the particle size of the nanoparticles in the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 2 is relatively large, about 100 nm.

[0110] Comparative Example 3

[0111] This comparative example 3 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, which differs from Example 1 in that a mixed gas having a carbon monoxide content of 15%, a hydrogen content of 5%, and an argon content of 80% is introduced into a quartz tube to prepare a carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0112] Fig. 9 This is a bright field image of a transmission electron microscope of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 3 of the present disclosure.

[0113] like Fig. 9 As shown, it can be observed that the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 3 is covered with significant carbon deposits.

[0114] Comparative Example 4

[0115] This comparative example 4 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, which differs from Example 1 in that the tubular furnace is heated to 550° C. at a heating rate of 1° C. / min to prepare a carbon-supported platinum-cobalt (PtCo) alloy catalyst.

[0116] Fig.10 It is the X-ray diffraction spectrum of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of the present disclosure.

[0117] like Fig.10 As shown, it can be observed that the (111) crystal plane diffraction peak position of the prepared PtCo alloy is significantly shifted to a lower angle compared with the ordered alloy, proving that its alloying degree is reduced.

[0118] Comparative Example 5

[0119] This comparative example 5 provides a method for preparing a carbon-supported platinum-cobalt (PtCo) alloy catalyst, which differs from Example 1 in that the carbon-supported platinum-cobalt (PtCo) alloy catalyst is prepared by lowering the temperature to 750°C at a rate of 0.5°C / min.

[0120] Fig.11 It is the X-ray diffraction spectrum of the carbon-supported platinum-cobalt alloy catalyst in Comparative Example 4 of the present disclosure.

[0121] like Fig.11 As shown, it can be observed that the superlattice characteristic peak of the prepared PtCo alloy almost disappears, proving that the content of ordered alloy therein is significantly reduced.

[0122] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for preparing a carbon-supported platinum-based alloy catalyst, characterized in that: The preparation method comprises: Providing an impregnation solution containing a platinum source and a non-precious metal source; Dispersing and impregnating the carbon-based carrier in the impregnation liquid, removing water, and obtaining a precursor mixture; The precursor mixture is calcined and annealed in a mixed atmosphere including hydrogen, carbon monoxide and an inert gas to obtain a carbon-supported platinum-based alloy catalyst.

2. The preparation method according to claim 1, characterized in that: The content of hydrogen in the mixed atmosphere is 3% to 10%, The carbon monoxide content is 1% to 15%, The content of the inert gas is 75% to 96%.

3. The preparation method according to claim 1, characterized in that: The platinum source includes any one of chloroplatinic acid, platinum acetylacetonate, platinum tetraammine nitrate, potassium chloroplatinate, sodium chloroplatinate, and ammonium chloroplatinate; The non-precious metal source is a soluble non-precious metal salt, and the soluble non-precious metal salt is selected from any one of nitrates or chlorides of vanadium, chromium, manganese, iron, cobalt, nickel, copper and zinc.

4. The preparation method according to claim 3, characterized in that: The molar ratio of the non-precious metal source to the platinum source is (0.3-1.5):1; The mass ratio of the carbon-based carrier, the platinum source and the non-precious metal source is 2:(6-10):(1.2-4.5).

5. The preparation method according to claim 1, characterized in that: The calcination and annealing process comprises: firstly heating the precursor mixture to a calcination temperature of 600°C to 1100°C at a rate of 0.5 to 5°C / min, keeping the temperature for reaction for 0.5 to 2 hours, then cooling the temperature to an annealing temperature of 450°C to 700°C at a rate of 0.1 to 3°C / min, and cooling to room temperature to obtain the carbon-supported platinum-based alloy catalyst.

6. The preparation method according to claim 1, characterized in that: The inert gas in the mixed atmosphere includes any one of argon, helium and nitrogen; The flow rate of the mixed atmosphere is 10-150 sccm.

7. A carbon-supported platinum-based alloy catalyst prepared by the preparation method according to claims 1 to 6, the catalyst comprising a carbon-based carrier and platinum-based alloy nanoparticles supported on the surface of the carbon-based carrier; wherein: The platinum-based alloy nanoparticles are alloys of platinum and non-noble metals.

8. The carbon-supported platinum-based alloy catalyst according to claim 7, characterized in that: The size of the platinum-based alloy nanoparticles is 3 to 10 nm; The platinum-based alloy content in the catalyst is 40% to 70%.

9. The carbon-supported platinum-based alloy catalyst according to claim 7, characterized in that: The proportion of ordered alloy in the alloy of platinum and non-precious metal is 30-50%.

10. Use of the carbon-supported platinum-based alloy catalyst according to any one of claims 7 to 9 in an oxygen reduction reaction.

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